Power amplifier output matching

ABSTRACT

A semiconductor-on-insulator die can include a power amplifier configured to amplify a radio frequency input signal having a fundamental frequency. The die can further include an output matching circuit including first and second second-order harmonic rejection circuits configured to resonate at about two times the fundamental frequency and a third order harmonic rejection circuit configured to resonate at about three times the fundamental frequency.

INCORPORATION BY REFERENCE TO ANY PRIORITY APPLICATIONS

Any and all applications for which a foreign or domestic priority claimis identified in the Application Data Sheet as filed with the presentapplication are hereby incorporated by reference under 37 CFR 1.57.

BACKGROUND Technical Field

Embodiments of this disclosure relate to radio frequency electronicsystems, such as front end systems and related devices, integratedcircuits, modules, and methods.

Description of Related Technology

A radio frequency electronic system can process radio frequency signalsin a frequency range from about 30 kilohertz (kHz) to 300 gigahertz(GHz), such as in a range from about 450 megahertz (MHz) to 6 GHz. Afront end system is an example of a radio frequency electronic system. Afront end system can be referred to as a radio frequency front endsystem. A front end system can process signals being transmitted and/orreceived via one or more antennas. For example, a front end system caninclude one or more switches, one or more filters, one or more low noiseamplifiers, one or more power amplifiers, other circuitry, or anysuitable combination thereof in one or more signal paths between one ormore antennas and a transceiver. Front end systems can include one ormore receive paths and one or more transmit paths.

A front-end system can include a power amplifier in a transmit path.Power amplifiers can be included in front-end systems in a wide varietyof communications devices to amplify an RF signal for transmission. AnRF signal amplified by a power amplifier can be transmitted via anantenna. Example communications devices having power amplifiers include,but are not limited to, Internet of Things (IoT) devices, mobile phones,tablets, base stations, network access points, laptops, computers, andtelevisions. As an example, in mobile phones that communicate using acellular standard, a wireless local area network (WLAN) standard, and/orany other suitable communication standard, a power amplifier can be usedto amplify the RF signal.

An output matching circuit can be included at the output of a poweramplifier. The output matching circuit can be used to increase powertransfer and/or reduce reflections of the amplified RF signal generatedby the power amplifier.

SUMMARY

According to certain aspects of the disclosure, a power amplifier systemincludes a semiconductor-on-insulator die. The system further includes apower amplifier implemented on the semiconductor-on-insulator die andconfigured to amplify a radio frequency input signal having afundamental frequency. The power amplifier can include an inputconfigured to receive the radio frequency input signal and an outputconfigured to provide an amplified radio frequency signal. The systemfurther includes an output matching circuit implemented on thesemiconductor-on-insulator die. The semiconductor-in-insulator die caninclude first and second second-order harmonic rejection circuitsconfigured to resonate at about two times the fundamental frequency anda third order harmonic rejection circuit configured to resonate at aboutthree times the fundamental frequency.

The power amplifier system can further include a third second-orderharmonic rejection circuit. The first and second second-order harmonicrejection circuits can be harmonic short circuits. The thirdsecond-order harmonic rejection circuit can be a harmonic open circuit.The third-order harmonic rejection circuit can be a harmonic opencircuit.

The first second-order harmonic rejection circuit can be positionedbetween the output of the power amplifier and a power low supplyvoltage. The third-order harmonic rejection circuit can be positionedbetween the output of the power amplifier and a first node. The thirdsecond-order harmonic circuit can be positioned between the first nodeand a second node. The second second-order harmonic circuit can bepositioned between the second node and the power low supply voltage.

The system can further include biasing circuitry implemented on the dieand configured to bias the power amplifier. The system can additionallyinclude a switch implemented on the die and configured to controlconnection of signal paths to an antenna.

The power amplifier can include two field effect transistors arranged ina cascode configuration.

The third-order harmonic rejection circuit can include a capacitor andan inductor. The inductor can be implemented as a surface mount deviceon a module supporting the semiconductor-on-insulator die. The firstsecond-order harmonic rejection circuit can include a tunable bank of atleast two capacitors. The system can further include a biasing circuitincluding a decoupling capacitor and a choke inductor. The chokeinductor can be embedded in a substrate of a module supporting thesemiconductor-on-insulator die.

According to additional aspects, a semiconductor-on-insulator dieincludes a power amplifier configured to amplify a radio frequency inputsignal having a fundamental frequency, the power amplifier including aninput configured to receive the radio frequency input signal and anoutput configured to provide an amplified radio frequency signal. Thedie further includes an output matching circuit including first andsecond second-order harmonic rejection circuits configured to resonateat about two times the fundamental frequency and a third order harmonicrejection circuit configured to resonate at about three times thefundamental frequency.

The die can further include a third second-order harmonic rejectioncircuit. The first and second second-order harmonic rejection circuitscan be harmonic short circuits and the third second-order harmonicrejection circuit is a harmonic open circuit. The third-order harmonicrejection circuit can be a harmonic open circuit.

The power amplifier can include two field effect transistors arranged ina cascode configuration.

The die can further include biasing circuitry configured to bias thepower amplifier, a switch configured to control connection of signalpaths to an antenna, and a controller configured to control the poweramplifier and the switch.

According to further aspects, a mobile device includes a moduleincluding a semiconductor-on-insulator die mounted thereon. The dieincludes a power amplifier configured to amplify a radio frequency inputsignal having a fundamental frequency. The power amplifier can includean input configured to receive the radio frequency input signal and anoutput configured to provide an amplified radio frequency signal. Thedie can further include an output matching circuit including first andsecond second-order harmonic rejection circuits configured to resonateat about two times the fundamental frequency and a third order harmonicrejection circuit configured to resonate at about three times thefundamental frequency. The mobile device can further include a radiofrequency antenna, which in some embodiments is included on the module.

The mobile device can further include a biasing circuit including adecoupling capacitor and a choke inductor. The decoupling capacitor canbe implemented on the die. The choke inductor can be embedded in asubstrate of the module. The third order harmonic rejection circuitincludes a capacitor implemented on the die and a surface mountedinductor mounted on the module.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A illustrates a schematic block diagram of one example of a frontend system.

FIG. 1B illustrates a schematic block diagram of another example of afront end system.

FIG. 2 is a schematic diagram showing portions of a transmit path of afront end system including an example of an output matching network.

FIG. 3 is a schematic diagram showing portions of a transmit path of afront end system including another example of an output matchingnetwork.

FIG. 4 depicts an example of a mobile device including a radio frequencymodule having a semiconductor-on-insulator die.

FIG. 5A is a schematic diagram of one embodiment of a packaged module.

FIG. 5B is a schematic diagram of a cross-section of the packaged moduleof FIG. 5A taken along the lines 5B-5B.

FIG. 6 is a schematic diagram of one example of an Internet of things(IoT) network.

FIG. 7A is a schematic diagram of one example of an IoT-enabled watch.

FIG. 7B is a schematic diagram of one example of a front end system foran IoT-enabled object.

FIG. 8A is a schematic diagram of one example of IoT-enabled vehicles.

FIG. 8B is a schematic diagram of another example of a front end systemfor an IoT-enabled object.

FIG. 9A is a schematic diagram of one example of IoT-enabled industrialequipment.

FIG. 9B is a schematic diagram of another example of a front end systemfor an IoT-enabled object.

FIG. 10A is a schematic diagram of one example of an IoT-enabled lock.

FIG. 10B is a schematic diagram of one example of a circuit board forthe IoT-enabled lock of FIG. 10A.

FIG. 11A is a schematic diagram of one example of an IoT-enabledthermostat.

FIG. 11B is a schematic diagram of one example of a circuit board forthe IoT-enabled thermostat of FIG. 11A.

FIG. 12A is a schematic diagram of one example of IoT-enabled light.

FIG. 12B is a schematic diagram of one example of a circuit board forthe IoT-enabled light of FIG. 12A.

FIG. 13A illustrates a schematic block diagram of one example of a radiofrequency system.

FIG. 13B illustrates a schematic block diagram of another example of aradio frequency system.

FIG. 13C illustrates a schematic block diagram of another example of aradio frequency system.

FIG. 13D illustrates a schematic block diagram of another example of aradio frequency system.

FIG. 14A is a schematic diagram of one example of a wirelesscommunication device.

FIG. 14B is a schematic diagram of another example of a wirelesscommunication device.

FIG. 14C is a schematic diagram of another example of a wirelesscommunication device.

FIG. 15 is a schematic diagram of an example of a radio frequency moduleaccording to an embodiment.

DETAILED DESCRIPTION OF CERTAIN EMBODIMENTS

The following detailed description of certain embodiments presentsvarious descriptions of specific embodiments. However, the innovationsdescribed herein can be embodied in a multitude of different ways, forexample, as defined and covered by the claims. In this description,reference is made to the drawings where like reference numerals canindicate identical or functionally similar elements. It will beunderstood that elements illustrated in the figures are not necessarilydrawn to scale. Moreover, it will be understood that certain embodimentscan include more elements than illustrated in a drawing and/or a subsetof the elements illustrated in a drawing. Further, some embodiments canincorporate any suitable combination of features from two or moredrawings.

Front End Systems

A front end system can be used to handle signals being transmittedand/or received via one or more antennas. For example, a front endsystem can include switches, filters, amplifiers, and/or other circuitryin signal paths between one or more antennas and a transceiver.

Implementing one or more features described herein in a front end systemcan achieve a number of advantages, including, but not limited to, oneor more of higher power added efficiency (PAE), more compact layout,lower cost, higher linearity, superior robustness to overstress, and/orenhanced integration. Moreover, implementing one or more featuresdescribed herein in a front end system can achieve desirable figure ofmerit (FOM) and/or other metrics by which front end systems are rated.Although some features are described herein in connection with front endsystems for illustrative purposes, it will be understood that theprinciples and advantages described herein can be applied to a widevariety of other electronics.

FIG. 1A illustrates a schematic block diagram of one example of a frontend system 10. The front end system 10 includes an antenna-side switch2, a transceiver-side switch 3, a bypass circuit 4, a power amplifier 5,an output matching network 9 connected to an output of the poweramplifier 5, a low noise amplifier (LNA) 6, and a control and biasingcircuit 7. The front end system 10 can incorporate one or more featuresdescribed in the sections herein.

Although one example of a front end system is shown in FIG. 1A, a frontend system can be adapted in a wide variety of ways. For example, afront end system can include more or fewer components and/or signalspaths. Accordingly, the teachings herein are applicable to front endsystems implemented in a wide variety of ways.

In certain implementations, a front end system, such as the front endsystem 10 of FIG. 1A, is implemented on an integrated circuit orsemiconductor die. In such implementations, the front end system can bereferred to as a front end integrated circuit (FEIC). In otherimplementations, a front end system is implemented as a module. In suchimplementations, the front end system can be referred to as a front endmodule (FEM).

Accordingly, in some implementations, the front end system 10 isimplemented in a packaged module. Such packaged modules can include arelatively low cost laminate and one or more dies that combine low noiseamplifiers with power amplifiers and/or switch functions. Some suchpackaged modules can be multi-chip modules. In certain implementations,some or the all of the illustrated components of the front end system 10can be embodied on a single integrated circuit or die. Such a die can bemanufactured using any suitable process technology. As one example, thedie can be a semiconductor-on-insulator die, such as asilicon-on-insulator (SOI) die. Using silicon-on-insulator or othersemiconductor-on-insulator technology and stacked transistor topologiescan enable power amplifiers to be implemented in relatively inexpensiveand relatively reliable technology. Moreover, the desirable performanceof low-noise amplifiers (LNAs) and/or multi-throw RF switches insilicon-on-insulator technology can enable a stacked transistorsilicon-on-insulator power amplifier to be implemented as part of acomplete front end integrated circuit (FEIC) solution that includestransmit, receive, and switching functionality with desirableperformance.

For example, in some embodiments the front end system 10 can be apackaged module including a semiconductor-on-insulator die implementinga FET-based class-F power amplifier 5 and an output matching network 9.Further details regarding such embodiments, and exemplary outputmatching networks are described in further detail herein, such as withrespect to FIGS. 2 and 3, for example.

As shown in FIG. 1A, the front end system 10 includes multiple signalpaths between the antenna-side switch 2 and the transceiver-side switch3. For example, the illustrated front end system 10 includes a bypasssignal path that includes the bypass circuit 4, a transmit signal paththat includes the power amplifier 5, and a receive signal path thatincludes the LNA 6. Although an example with three signal paths isshown, a front end system can include more or fewer signal paths.

The antenna-side switch 2 is used to control connection of the signalpaths to an antenna (not shown in FIG. 1A). For example, theantenna-side switch 2 can be used to connect a particular one of thetransmit signal path, the receive signal path, or the bypass signal pathto an antenna. Additionally, the transceiver-side switch 3 is used tocontrol connection of the signal paths to a transceiver (not shown inFIG. 1A). For example, the transceiver-side switch 3 can be used toconnect a particular one of the transmit signal path, the receive signalpath, or the bypass signal path to a transceiver. In certainimplementations, the antenna-side switch 2 and/or the transceiver-sideswitch 3 are implemented as multi-throw switches.

FIG. 1B illustrates a schematic block diagram of another example of afront end system 20. The front end system 20 of FIG. 1B is similar tothe front end system 10 of FIG. 1A, except that the front end system 20further includes an integrated antenna 11. In certain implementations, afront end system includes an integrated antenna. For example, a frontend system can be implemented on a module along with one or moreintegrated antennas.

With reference to FIGS. 1A and 1B, the bypass network 4 can include anysuitable network for matching and/or bypassing the receive signal pathand the transmit signal path. The bypass network 4 can be implemented,for instance, by a passive impedance network or by a conductive trace orwire.

The power amplifier 5 can be used to amplify a transmit signal receivedfrom a transceiver for transmission via an antenna. The power amplifier5 can be implemented in a wide variety of ways.

In certain implementations, the power amplifier 5 is a class F amplifierincluding two field-effect transistors implemented in a cascodearrangement (see, e.g., FIG. 3). Such a stacked power amplifier topologycan be advantageous in semiconductor-on-insulator process technologies.For instance, device stacking for silicon-on-insulator power amplifiercircuit topologies can overcome relatively low breakdown voltages ofscaled transistors. Such device stacking can be beneficial inapplications in which a stacked amplifier is exposed to a relativelylarge voltage swing, such as a voltage swing exceeding about 2.75 Volts.Stacking several transistors, such as 2, 3, 4 or more transistors, canresult in a power amplifier with desirable operating characteristics.

In additional embodiments, the power amplifier 5 can include a stackedoutput stage and a bias circuit that biases the stacked transistors ofthe stacked output stage based on mode. In one example, the bias circuitcan bias a transistor in a stack to a linear region of operation in afirst mode, and bias the transistor as a switch in a second mode.Accordingly, the bias circuit can bias the stacked output stage suchthat the stacked output stage behaves like there are fewer transistorsin the stack in the second mode relative to the first mode. Suchoperation can result in meeting design specifications for differentpower modes, in which a supply voltage provided to the stacked outputstage changes based on mode.

In certain implementations, the power amplifier 5 can include a driverstage implemented using an injection-locked oscillator and an outputstage having an adjustable supply voltage that changes with a mode ofthe power amplifier 5. By implementing the power amplifier 5 in thismanner, the power amplifier 5 exhibits excellent efficiency, includingin a low power mode. For example, in the low power mode, the adjustablesupply voltage used to power the output stage is decreased, and thedriver stage has a relatively large impact on overall efficiency of thepower amplifier 5. By implementing the power amplifier 5 in this manner,the power amplifier's efficiency can be enhanced, particularly inapplications in which the power amplifier's output stage operates withlarge differences in supply voltage in different modes of operation.

The LNA 6 can be used to amplify a received signal from the antenna. TheLNA 6 can be implemented in a wide variety of ways.

In some embodiments, the LNA 6 is implemented with magnetic couplingbetween a degeneration inductor (e.g., a source degeneration inductor oran emitter degeneration inductor) and a series input inductor. Thesemagnetically coupled inductors can in effect provide a transformer, witha primary winding in series with the input and a secondary windingelectrically connected where the degeneration inductor is electricallyconnected to the amplifying device (e.g., at the source of a fieldeffect transistor amplifying device or at the emitter of a bipolartransistor amplifying device). Providing magnetically coupled inductorsin this manner allows the input match inductor to have a relatively lowinductance value and corresponding small size. Moreover, negativefeedback provided by the magnetically coupled inductors can provideincreased linearity to the LNA 6.

In certain embodiments, the LNA 6 and the antenna-side switch 2 areimplemented in accordance with one or more features of Section II(Overload Protection of Low Noise Amplifier). For example, theantenna-side switch 2 can include an analog control input forcontrolling an impedance between an antenna and an input to the LNA 6.Additionally, an overload protection circuit is included to providefeedback to the switch's analog control input based on detecting asignal level of the LNA 6. Thus, the overload protection circuit detectswhether or not the LNA 6 is overloaded. Additionally, when the overloadprotection circuit detects an overload condition, the overloadprotection circuit provides feedback to the analog control input of theswitch to increase the impedance of the switch and reduce the magnitudeof the input signal received by the LNA 6. Implementing the LNA 6 andthe antenna-side switch 2 in this manner limits large current and/orvoltage swing conditions manifesting within amplification transistors ofthe LNA 6.

With continuing reference to FIGS. 1A and 1B, the control and biasingcircuit 7 can be used to control and bias various front end circuitry.For example, the control and biasing circuit 7 can receive controlsignal(s) for controlling the LNA 6, the antenna-side switch 2, thetransceiver-side switch 3, and/or the power amplifier 5. The controlsignals can be provided to the control and biasing circuit 7 in avariety of ways, such as over an input pad of a die. In one example, thecontrol signals include at least one of a mode signal or a bias controlsignal.

The front end system 10 of FIG. 1A and the front end system 20 of FIG.1B can be implemented on one or more semiconductor dies. In certainimplementations, at least one of the semiconductor dies includes pins orpads protected using an electrical overstress (EOS) protection circuit.For example, an EOS protection circuit can include an overstress sensingcircuit electrically connected between a pad of a semiconductor die anda first supply node, an impedance element electrically connected betweenthe pad and a signal node, a controllable clamp electrically connectedbetween the signal node and the first supply node and selectivelyactivatable by the overstress sensing circuit, and an overshoot limitingcircuit electrically connected between the signal node and a secondsupply node. The overstress sensing circuit activates the controllableclamp when an EOS event is detected at the pad. Thus, the EOS protectioncircuit is arranged to divert charge associated with the EOS event awayfrom the signal node to provide EOS protection. By implementing a frontend system in this manner can achieve enhanced EOS protection, lowerstatic power dissipation, and/or a more compact chip layout. In certainimplementations, the pad is an input pad that receives a control signalfor controlling the power amplifier 5 and/or LNA 6.

In accordance with certain embodiments, the front end systems of FIGS.1A and/or 1B can include RF shielding and/or RF isolation structures.For example, the front end system can be implemented as a radiofrequency module that is partially shielded. Additionally, a shieldinglayer is included over a shielded portion of the radio frequency moduleand an unshielded portion of the radio frequency module is unshielded.The shielding layer can shield certain components of the front endsystem (for instance, the power amplifier 5 and/or LNA 6) and leaveother components (for instance, the integrated antenna 11) unshielded.

In certain implementations, the front end systems of FIGS. 1A and/or 1Bcan include a laminated substrate including an antenna is printed on atop layer and a ground plane for shielding on a layer underneath the toplayer. Additionally, at least one electronic component of the front endcan be disposed along a bottom layer of the laminate substrate, andsolder bumps are disposed around the electronic component andelectrically connected to the ground plane. The solder bumps can attachthe module to a carrier or directly to a system board. The electroniccomponent can be surrounded by solder bumps, and the outside edges ofthe electronic component can have ground solder bumps that are connectedto the ground plane by way of vias. Accordingly, a shielding structurewith can be completed when the module is placed onto a carrier or systemboard, and the shielding structure can serve as a Faraday cage aroundthe electronic component.

In certain embodiments, the front end systems disclosed herein areimplemented on a semiconductor die as front end integrated circuit(FEIC). The FEIC can be included in a packaged module that stacksmultiple chips and passive components, such as capacitors and resistors,into a compact area on a package substrate. By implementing an FEIC insuch a packaged module, a smaller footprint and/or a more compactsubstrate area can be achieved.

In accordance with certain embodiments, a packaged module includes aFEIC, a crystal oscillator and a system on a chip (SoC), such as atransceiver die. The SoC can be stacked over a crystal assembly to savespace and provide shorter crystal traces. The crystal assembly includesthe crystal oscillator housed in a housing that includes one or moreconductive pillars for routing signals from the SoC to a substrateand/or to provide thermal conductivity.

In accordance with certain embodiments, a packaged module includes aFEIC, a filter assembly and a SoC. For example, the filter assembly canbe stacked with other dies and components of the packaged module toreduce a footprint of the packaged module. Furthermore, stacking thefilter assembly in this manner can reduce lengths of signal carryingconductors, thereby reducing parasitics and enhancing signalingperformance.

A system in a package (SiP) can include integrated circuits and/ordiscrete components within a common package. Some or all of a front endsystem can be implemented in a SiP. An example SiP can include asystem-on-a-chip (SoC), a crystal for clocking purposes, and a front-endmodule (FEM) that includes a front end system. In certain SiPs, a SoCand a crystal can consume a relatively large amount of physical area.This can create a relatively large footprint for the SiP.

Power Amplifier Output Matching

FIG. 2 is a schematic diagram showing portions of transmit path of apower amplifier front end 10, including a power amplifier 5, a supplyvoltage biasing circuit 15, an output matching circuit 9 (also referredto as an output matching network), and at least one RF front endcomponent 12. For example, the front end component 12 can include aswitch such as the antenna-side switch 2 of FIG. 1A/1B, which connectsthe transmit path to an antenna 14, which can either be integratedtogether with the front end 10 (e.g., FIG. 1B) or external to the frontend 10 (e.g., FIG. 1A).

The power amplifier 5 includes an input configured to receive a radiofrequency signal RF_IN and an output electrically connected to an inputnode of the output matching circuit 9. The output matching circuit 9further includes an output node electrically connected to an input ofthe RF front end component 12. The RF front end component 12 include anoutput electrically connected to the antenna 14.

The illustrated power amplifier 5 can include one or more field effecttransistors implemented in a semiconductor-on-insulator die, one exampleof which is depicted in FIG. 3. Referring to FIGS. 2 and 3, the poweramplifier illustrated in FIG. 3 includes first and second field effecttransistors (FETs) 17, 19 connected in a stacked cascade configuration.For example, the first and second FETs 17, 19 can besemiconductor-on-insulator (e.g., silicon-on-insulator) transistors.Each FET includes a gate, drain, and source. The first FET 17 isconnected in a common-gate configuration with the gate electricallyconnected to a power low supply voltage V₁, which can be a groundsupply. The source of the first FET 17 is connected to the drain of thesecond FET 19. The second FET 19 is connected in a common-sourceconfiguration, with the source connected to the first power low supplyvoltage V₁. The gate of the second FET 19 is configured to receive thesignal RF_IN. During operation, the power amplifier 5 can amplify thesignal RF_IN, and provide the amplified signal at the drain of the firstFET 17, which operates as the output of the power amplifier 5. The firstand second FETs 17, 19 can be any suitable FET devices. Although FIG. 3illustrates one implementation of the power amplifier 5, the teachingsdescribed herein can be applied to a variety of power amplifierstructures, including, for example, multi-stage power amplifierstructures and/or power amplifiers employing other transistor types,including, for example, bipolar transistors.

The power amplifier 5 in certain embodiments is a class F poweramplifier. This can be advantageous in implementations where the poweramplifier 5 is implemented in a semiconductor-on-insulator complementarymetal oxide semiconductor (CMOS) process technology, or other CMOSprocess technology, because CMOS process technologies can have limitedvoltage handling capabilities as compared to other process technologies(e.g., Gallium Arsenide), and class F amplifiers can be well-suitedunder these circumstances. In other embodiments, other types ofamplifiers such as class AB, inverted class F, or class E can be used.

Particularly where a class F amplifier is used, it can be desirable forthe output matching circuit 9 to implement an effective second orderharmonic short circuit and third order harmonic open circuit. Thus, theoutput matching circuits 9 of FIGS. 2 and 3 can be configured to provideenough rejection on the second and third order harmonics.

Referring to FIGS. 2 and 3, the output of the power amplifier 5 and theinput of the output matching circuit 9 are connected to the supplyvoltage biasing circuit 15. As shown in FIG. 3, the supply voltagebiasing circuit 15 can be electrically connected between the power highsupply voltage V_(CC) and the input node of the output matching network9. The supply voltage biasing circuit 15 can be used to bias the poweramplifier 5 with the power high supply voltage V_(CC), which in certainimplementations is generated by an envelope tracker or other supplycontrol block. The supply voltage biasing circuit 15 includes aninductor 21 and a capacitor 23. The inductor can be referred to as achoke inductor 21 and includes a first end electrically connected to thepower high supply voltage V_(CC) and a second end electrically connectedto the drain of the first FET 17 at the output of the power amplifier 5.The choke inductor 21 can have an inductance sufficient to block RFsignals generated by the power amplifier 5 from reaching the power highsupply voltage V_(CC). However, the choke inductor 21 should be sized tominimize L*dI/dt effects associated with receiver band noise, which candegrade performance in envelope tracking applications. The capacitor 23can be referred to as a decoupling capacitor 23 and includes a first endelectrically connected to the power high supply voltage V_(CC) and asecond end electrically connected to the power low supply voltage V₁,and can perform a wide variety of functions. For example, including thedecoupling capacitor 23 can reduce noise of the power high supplyvoltage V_(CC) and/or stabilize the output of the power amplifier 5.Additionally, the decoupling capacitor 23 can be used to provide anRF/AC ground to the second end of the choke inductor 21.

The choke inductor 21 in some embodiments is not implemented on the samedie as the other components shown in FIG. 2. For instance, in oneembodiment the choke inductor 21 is embedded in metal layers of a modulelaminate or substrate, as is further described with respect to FIG. 4.Such an embedded inductor can provide improved current handling. Inanother embodiment, the choke inductor 21 is implemented on the same dieas other components illustrated in FIG. 2, such as the power amplifier,output matching network, and front end component 12. In yet anotherembodiment the choke inductor 21 is a surface mount component.

In various embodiments, the choke inductor 21 has an inductance in therange of about 1 nH to about 6 nH and the decoupling capacitor 23 has acapacitance in the range of about 0 nF (omitted) to about 5 nF. In oneembodiment, the choke inductor 21 has an inductance of 1.1 nH and thedecoupling capacitor 23 has a capacitance of 2.7 nF. However, othersuitable inductance and capacitance values can be used, such asinductance and capacitance values associated with optimum load impedanceand/or operating frequency.

The output matching network 9 includes first and second matchingcapacitors C1, C4, first and second second-order harmonic short circuits25, 31, a third-order harmonic open circuit 27, a second order harmonicrejection circuit 29, and a DC blocking capacitor C7.

The first matching capacitor C1 and the second first second-orderharmonic short circuit 25 are each electrically connected between theinput node of the output matching network 9 and the power low supplyvoltage V₁. The third-order harmonic open circuit 27 is connectedbetween the input node of the output matching network 9 and the firstnode 33. The second matching capacitor C4 is connected between the firstnode 33 and the power low supply voltage V₁. The second order harmonicopen circuit 29 is connected between the first node 33 and a second node35. The second second-order harmonic short circuit 31 is connectedbetween the second node 35 and the power supply low node V₁. The DCblocking capacitor is connected between the second node 35 and theoutput node of the output matching network 9.

The first and second matching capacitors C1, C4 can be configured tomatch impedance of the output of the power amplifier 5.

The first and second second-order harmonic short circuits 25, 31 can beconfigured to resonate at about two times the fundamental frequency ofthe signal RF_IN so as to short second-order harmonic frequency signalcomponents in the power amplifier's output signal. In the illustratedconfiguration, the first second-order harmonic short circuit 25 includesan inductor L1 and a capacitor C2 electrically connected in seriesbetween the power low supply voltage V₁ and the input node of the outputmatching network 9, which is also the output of the power amplifier 5and, referring now only to FIG. 3, the drain of the first FET 17. Thesecond second-order harmonic short circuit 31 includes an inductor L4and a capacitor C6 electrically connected in series. Although the firstand second second-order harmonic short circuits 25, 31 illustrateexemplary configurations, other configurations can be used, including,for example, implementations in which the order of the inductors and thecapacitors in the series are reversed.

In one embodiment, the first second-order harmonic short circuit 25 isconfigured to resonate such that the impedance of the first second-orderharmonic series resonant circuit 25 at two times the fundamentalfrequency of the signal RF_IN is less than about 1Ω. The firstsecond-order harmonic short circuit 25 can be configured to resonatesuch that the impedance of the first second-order harmonic seriesresonant circuit 25 at two times the fundamental frequency of the signalRF_IN is less than about 20% of a load line impedance (e.g., a 5Ω loadline impedance) of the output matching circuit 9.

The third-order harmonic open circuit 27 includes a capacitor C3 and aninductor L2 connected in parallel. The third-order harmonic open circuit27 can be configured to resonate at about three times the fundamentalfrequency of the signal RF_IN and act as an open circuit, therebyblocking third-order harmonic frequency components generated by theoutput signal of the power amplifier 5 from reaching the first node 33.

The third-order harmonic open circuit 27 can improve the third-orderharmonic rejection of the power amplifier 5 by providing high impedanceto signals at about three times the fundamental frequency of the signalRF_IN. In one embodiment, the inductor L2 and the capacitor C3 areconfigured to resonate such that the impedance of the third-orderharmonic parallel resonant circuit 27 at three times the fundamentalfrequency of the signal RF_IN is greater than about 50 kΩ. The inductorL2 and the capacitor C3 can be configured to resonate such that theimpedance of the third-order harmonic open circuit 27 at three times thefundamental frequency of the signal RF_IN is greater than about 10000times a load line impedance (e.g., a 5Ω load line impedance) of theoutput matching circuit 9.

The second order harmonic open circuit 29 includes a capacitor C5 and aninductor L3 connected in parallel. The second order harmonic opencircuit 29 is configured to resonate at about two times the fundamentalfrequency of the signal RF_IN and act as an open circuit, therebyblocking second-order harmonic frequency components generated by theoutput signal of the power amplifier 5 from reaching the second node 33.Thus, the second order harmonic open circuit 29 serves to supplement thesecond order harmonic rejection provided by the first and secondsecond-order harmonic short circuits 25, 31.

The output matching circuit 9 further includes the DC blocking capacitorC7, which is electrically connected between the second node 35 and theoutput node of the output matching circuit 9. The DC blocking capacitorC7 can provide DC blocking and/or help provide an impedancetransformation to achieve a desired load line impedance of the poweramplifier 5 at the fundamental frequency. For example, in certainimplementations the DC blocking capacitor C7 can be used at least inpart to transform a termination impedance associated with the RF frontend 10, such as a 50Ω termination impedance, to a load line impedancethat is desirable for the power amplifier 5 from a power efficiencystandpoint. Additionally, the DC blocking capacitor C7 can block DCsignals, thereby helping to provide DC bias voltage isolation betweenthe output of the power amplifier 5 and the input of the RF front end10. Although FIGS. 2 and 3 illustrate a configuration including the DCblocking capacitor C7, in certain implementations the DC blockingcapacitor C7 can be omitted, such as in implementations using a surfaceacoustic wave (SAW) filter.

Although the output matching circuit 9 has been illustrated in thecontext of one example of a power amplifier system, the output matchingcircuit 9 can be used in other configurations of power amplifiersystems.

Referring now only to FIG. 3, the illustrated embodiment shows animplementation in which the capacitor C2 is implemented using a tunablebank of three switched capacitors C2 a, C2 b, C2 c instead of the singlecapacitor C2 shown in the implementation of FIG. 2. The switches SW1 andSW0 are connected in series with the capacitors C2 b and C2 crespectively, such that the overall capacitance of C2 can be tuned. Inparticular, the overall capacitance can be tuned to one of threevalues: 1) C2 a (where SW1 and SW0 are both off/open); 2) C2 a+C2 b(where SW1 is on/closed, SW0 is off/open); or 3) C2 a+C2 b+C2 c (whereSW1 and SW0 are both on/closed). In this manner, the front end 10 candynamically adjust the output matching network to optimize the secondorder rejection provided by the first second-order short circuit 25.

While only the first second-order short circuit 25 is shown as having adynamically adjustable capacitance value, any combination of one or moreof the other capacitance or inductor values can be similar dynamicallyadjustable, e.g., by incorporating additional capacitors, inductors, andcorresponding switches, as appropriate.

FIG. 3 shows the inductor L2 being implemented as an off-die componentinstead, not included on the same die as the other components of theoutput matching network 9. For instance, the inductor L2 can be asurface mount component mounted on a substrate of a module. Behavior orthe output matching network 9 can be particularly sensitive to theprecise value of L2, and a surface mount implementation of L2 can reducethe cost of selecting/adjusting the value of L2 as needed. While only L2is shown as being a surface mount component in FIG. 3, any of the othercapacitors or inductors can be surface mount components in otherembodiments. In some embodiments, L2 is included on the same die (e.g.,a semiconductor-on-insulator die) as the other components of the outputmatching network 9.

FIG. 4 depicts an example of a mobile device 400 including a radiofrequency module 402 having a semiconductor-on-insulator die 404. Asshown, the semiconductor-on-insulator die can include a front end system10, which can be any of the front end systems described herein includingthose described previously with respect to FIGS. 1A-3. The mobile device400 can be an Internet of Things (IoT) capable device, for example.Additional details regarding compatible IoT networks and devices areprovided herein, including in the section entitled Internet of ThingsApplications. The mobile device 400 of FIG. 4 can comprise or beincorporated into any of the IoT devices described in that section orelsewhere herein. In other embodiments, the mobile device 400 is amobile phone

The front end system 10 includes one or more power amplifiers 5, anoutput matching network 9, one or more switches, and a controller 7. Thepower amplifiers 5 can be similar to or the same as the similarlynumbered power amplifiers in FIGS. 1-3, and can in some embodiments be acascode FET-based class F amplifier such as the power amplifier 5 ofFIG. 3. The output matching network 9 is configured to increase thepower transfer and/or reduce reflections of the amplified RF signalgenerated by the power amplifier 5, and can be any of the outputmatching networks described herein. The switch 12 can include one ormore of the antenna-side switch 2 and transceiver-side switch 3 of FIGS.1A-1B, or the RF component 12 of FIGS. 2-3. The controller 7 can besimilar to or the same as the control and biasing circuit 7 of FIGS.1A-1B, and can be used to control and bias the components of thefront-end system 10. As one example, the controller 7 can include thebiasing circuit 15 of FIGS. 2-3, and can be configured to control theswitches SW0, SW1 of FIG. 3 to tune the capacitance C2.

While not shown in FIG. 4, the front end system 10 can includeadditional components, such as one or more LNAs, additional switches,bypass circuitry, or the like.

The module 402 can include one or more surface mount devices 406 mountedon the module substrate, and one or more embedded devices 408 embeddedin metal layers of a laminate substrate of the module 402. The surfacemount devices 406 and embedded devices 408 can include inductors,capacitors, or other electrical components. For example, referring toFIG. 3, the surface mount devices 406 can include the inductor L2, andthe embedded devices 408 can include the choke inductor 21.

In one embodiment, the module 400 implements at least a LTE-Mcommunication standard and incorporates a CMOS silicon-on-insulator die404, eight surface mount devices 406 including the inductor L2, and oneembedded device comprising the choke inductor L1.

While not shown, the module 406 can include additional components,including some or all of a transceiver, baseband processor, memory,antenna, and the like (see, e.g., FIGS. 13A-15). Moreover, in someembodiments the mobile device 400 includes one or more additionalmodules or other components not shown in FIG. 4, which can implement oneor more of a transceiver, baseband processor, memory, antenna, or otherappropriate componentry.

According to certain embodiments, the use of asemiconductor-on-insulator (e.g., silicon-on-insulator CMOS) processtechnology allows for the incorporation on a single die 404 multiplefunctional elements, whereas other previous solutions utilize multipledies of different process technologies. Such single-die configurationscan be particularly well-suited for Internet of Things applications andcorresponding communication technologies.

The mobile devices and corresponding front end systems described hereincan implement a variety of communication standards including LTE-M (LTEMachine Type Communication), Bluetooth, ZigBee, Z-Wave, 6LowPAN, Thread,Wi-Fi, NFC, Sigfox, Neul, and/or LoRaWAN technologies. Furthermore,according to certain embodiments the mobile devices and correspondingfront end systems can be configured to communicate using cellularinfrastructure, for instance, using 2G, 3G, 4G (including LTE,LTE-Advanced, and/or LTE-Advanced Pro), and/or 5G technologies.

Packaged Modules

FIG. 5A is a schematic diagram of one embodiment of a packaged module900 which can incorporate any of the front end systems described hereinor otherwise be incorporated into any of the mobile devices includedherein. For example, the module 900 may correspond to the module 400 ofFIG. 4. FIG. 5B is a schematic diagram of a cross-section of thepackaged module 900 of FIG. 5A taken along the lines 5B-5B.

The packaged module 900 includes radio frequency components 901, asemiconductor die 902, surface mount devices 903, wirebonds 908, apackage substrate 920, and an encapsulation structure 940. For example,the semiconductor die 902 can be the semiconductor die 404 of FIG. 4,and can incorporate the front end systems 10 of FIG. 1A, 2, or 3, thefront end system 20 of FIG. 1B. The package substrate 920 includes pads906 formed from conductors disposed therein. Additionally, thesemiconductor die 902 includes pins or pads 904, and the wirebonds 908have been used to connect the pads 904 of the die 902 to the pads 906 ofthe package substrate 920.

The semiconductor die 902 includes a power amplifier 945, which can beimplemented in accordance with one or more features disclosed herein.While only the power amplifier 945 is shown for simplicity, it will beappreciated that additional componentry including any of the outputmatching networks, LNAs, switches, controllers, and the like can beincluded.

The packaging substrate 920 can be configured to receive a plurality ofcomponents such as radio frequency components 901, the semiconductor die902 and the surface mount devices 903, which can include, for example,surface mount capacitors and/or inductors. In one implementation, theradio frequency components 901 include integrated passive devices(IPDs).

As shown in FIG. 5B, the packaged module 900 is shown to include aplurality of contact pads 932 disposed on the side of the packagedmodule 900 opposite the side used to mount the semiconductor die 902.Configuring the packaged module 900 in this manner can aid in connectingthe packaged module 900 to a circuit board, such as a phone board of amobile device. The example contact pads 932 can be configured to provideradio frequency signals, bias signals, and/or power (for example, apower supply voltage and ground) to the semiconductor die 902 and/orother components. As shown in FIG. 5B, the electrical connectionsbetween the contact pads 932 and the semiconductor die 902 can befacilitated by connections 933 through the package substrate 920. Theconnections 933 can represent electrical paths formed through thepackage substrate 920, such as connections associated with vias andconductors of a multilayer laminated package substrate.

In some embodiments, the packaged module 900 can also include one ormore packaging structures to, for example, provide protection and/orfacilitate handling. Such a packaging structure can include overmold orencapsulation structure 940 formed over the packaging substrate 920 andthe components and die(s) disposed thereon.

It will be understood that although the packaged module 900 is describedin the context of electrical connections based on wirebonds, one or morefeatures of the present disclosure can also be implemented in otherpackaging configurations, including, for example, flip-chipconfigurations.

Internet of Things Applications

As mentioned previously, one example application of the front endsystems herein is to enable various objects with wireless connectivity,such as for Internet of things (IoT). IoT refers to a network of objectsor things, such as devices, vehicles, and/or other items that areembedded with electronics that enable the objects to collect andexchange data (for instance, machine-to-machine communications) and/orto be remotely sensed and/or controlled. The front end systems hereincan be used to enable wireless connectivity of various objects, therebyallowing such objects to communicate in an IoT network. The front endsystems discussed herein can be implemented in IoT applications toenable wireless connectivity to expand the way consumers manageinformation and their environment. Such front end systems can enable thenew and emerging IoT applications, which can bring people and thingscloser to vital information wherever it is desired. Although IoT is oneexample application of front end systems herein, the teachings hereinare applicable to a wide range of technologies and applications. Someexample IoT applications will now be discussed.

IoT devices can be implemented in automotive systems. From telematics toinfotainment systems, lighting, remote keyless entry, collisionavoidance platforms, toll transponders, video displays, vehicle trackingtools, and the like, front end systems in accordance with any suitableprinciples and advantages discussed herein can help enable convenienceand safety features for the connected vehicle.

IoT devices can be implemented in connected home environments. Front endsystems in accordance with any suitable principles and advantagesdiscussed herein can allow homeowners greater control over their homeenvironment. IoT devices can be implemented in a host of devicesincluding smart thermostats, security systems, sensors, light switches,smoke and carbon monoxide alarms, routers, high definition televisions,gaming consoles and much more.

IoT devices can be implemented in industrial contexts. From smart cityapplications to factory automation, building controls, commercialaircraft, vehicle tracking, smart metering, LED lighting, securitycameras, and smart agriculture functions, front ends systems inaccordance with any suitable principles and advantages discussed hereincan enable these applications and meet specifications.

IoT devices can be implemented in machine-to-machine contexts. IoTdevices can enable machine-to-machine communications that can transformthe way organizations do business. From manufacturing automation totelemetry, remote control devices, and asset management, front endsystems discussed herein can provide cellular, short-range, and globalpositioning solutions that support a wide range of machine-to-machineapplications.

IoT devices can be implemented in medical applications. Front endsystems in accordance with any suitable principles and advantagesdiscussed herein can enable medical devices and the communication ofinformation that is improving the care of millions of people worldwide.Front end systems in accordance with any suitable principles andadvantages discussed herein can be integrated into product designs thatenable the miniaturization of medical devices and enhance datatransmission. Amplifiers, such as power amplifiers and low noiseamplifiers, in accordance with any suitable principles and advantagesdiscussed herein can be implemented in medical instruments.

IoT devices can be implemented in mobile devices. The communicationlandscape has changed in recent years as consumers increasingly seek tobe connected everywhere and all the time. Front end systems inaccordance with any suitable principles and advantages discussed hereincan be compact, energy and cost efficient, meeting size and performanceconstraints, while enabling a great consumer experience. Wireless mobiledevices, such as smartphones, tablets and WLAN systems, can include afront end system in accordance with any suitable principles andadvantages discussed herein.

IoT devices can be implemented in smart energy applications. Utilitycompanies are modernizing their systems using computer-based remotecontrol and automation that involves two-way communication. Somebenefits to utilities and consumers include optimized energy efficiency,leveling and load balancing on the smart grid. Front end systems inaccordance with any suitable principles and advantages discussed hereincan be implemented in smart meters, smart thermostats, in-home displays,LTE-M (LTE Machine Type Communication), ZigBee/802.15.4, Bluetooth, andBluetooth low energy applications.

IoT devices can be implemented in wearable devices. Wearable devices,such as smartwatches, smart eyewear, fitness trackers and healthmonitors, can include front end systems in accordance with any suitableprinciples and advantages discussed herein to enable relatively smallform factor solutions that consume relatively low power and enablealways on connectivity. This can allow applications to run in thebackground for lengthy periods of time without a battery recharge, forexample.

Any suitable principles and advantages discussed herein can implementedin an IoT network, IoT object, a vehicle, industrial equipment, acorresponding front end system, a corresponding circuit board, the like,or any suitable combination thereof. Some examples will now bediscussed.

FIG. 6 is a schematic diagram of one example of an IoT network 200. TheIoT network 200 includes a smart home 201, a smart vehicle 202, awearable 203, a mobile device 204, a base station 205, a smart hospital206, a smart factory 207, and a smart satellite 208. One or more of theIoT-enabled objects of FIG. 6 can include a front end system, such as afront end module and/or front-end integrated circuit, implemented inaccordance with the teachings herein.

The smart home 201 is depicted as including a wide variety ofIoT-enabled objects, including an IoT-enabled router 211, an IoT-enabledthermostat 212, an IoT-enabled meter 213, IoT-enabled laptop 214, and anIoT-enabled television 215. Although various examples of IoT-enableobjects for a smart home are shown, a smart home can include a widevariety of IoT-enabled objects. Examples of such IoT-enabled objectsinclude, but are not limited to, an IoT-enabled computer, an IoT-enabledlaptop, an IoT-enabled tablet, an IoT-enabled computer monitor, anIoT-enabled television, an IoT-enabled media system, an IoT-enabledgaming system, an IoT-enabled camcorder, an IoT-enabled camera, anIoT-enabled modem, an IoT-enabled router, an IoT-enabled kitchenappliance, an IoT-enabled telephone, an IoT-enabled air conditioner, anIoT-enabled washer, an IoT-enabled dryer, an IoT-enabled copier, anIoT-enabled facsimile machine, an IoT-enabled scanner, an IoT-enabledprinter, an IoT-enabled scale, an IoT-enabled home assistant (forinstance, a voice-controlled assistant device), an IoT-enabled securitysystem, an IoT-enabled thermostat, an IoT-enabled smoke detector, anIoT-enabled garage door, an IoT-enabled lock, an IoT-enabled sprinkler,an IoT-enabled water heater, and/or an IoT-enabled light.

As shown in FIG. 6, the smart vehicle 202 also operates in the IoTnetwork 200. The smart vehicle 202 can include a wide variety ofIoT-enabled objects, including, but not limited to, an IoT-enabledinfotainment system, an IoT-enabled lighting system, an IoT-enabledtemperature control system, an IoT-enabled lock, an IoT-enabledignition, an IoT-enabled collision avoidance system, an IoT-enabled tolltransponder, and/or an IoT-enabled vehicle tracking system. In certainimplementations, the smart vehicle 202 can communicate with other smartvehicles to thereby provide vehicle-to-vehicle (V2V) communications.Furthermore, in certain implementations the smart vehicle 202 canoperate using vehicle-to-everything (V2X) communications, therebycommunicating with traffic lights, toll gates, and/or other IoT-enabledobjects.

The wearable 203 of FIG. 6 is also IoT-enabled. Examples of IoT-enabledwearables include, but are not limited to, an IoT-enabled watch, anIoT-enabled eyewear, an IoT-enabled fitness tracker, and/or anIoT-enabled biometric device.

The IoT network 200 also includes the mobile device 204 and base station205. Thus, in certain implementations user equipment (UE) and/or basestations of a cellular network can operate in an IoT network and beIoT-enabled. Furthermore, a wide variety of IoT-enabled objects cancommunication using existing network infrastructure, such as cellularinfrastructure.

With continuing reference to FIG. 6, IoT is not only applicable toconsumer devices and objects, but also to other applications, such asmedical, commercial, industrial, aerospace, and/or defense applications.For example, the smart hospital 206 can include a wide variety ofIoT-enabled medical equipment and/or the smart factory 207 can include awide variety of IoT-enabled industrial equipment. Furthermore,airplanes, satellites, and/or aerospace equipment can also be connectedto an IoT network. Other examples of IoT applications include, but arenot limited to, asset tracking, fleet management, digital signage, smartvending, environmental monitoring, city infrastructure (for instance,smart street lighting), toll collection, and/or point-of-sale.

Although various examples of IoT-enabled objects are illustrated in FIG.6, an IoT network can include a wide variety of types of objects.Furthermore, any number of such objects can be present in an IoTnetwork. For instance, an IoT network can include millions or billionsof IoT-enable objects or things.

IoT-enabled objects can communicate using a wide variety ofcommunication technologies, including, but not limited to, LTE-M (LTEMachine Type Communication), Bluetooth, ZigBee, Z-Wave, 6LowPAN, Thread,Wi-Fi, NFC, Sigfox, Neul, and/or LoRaWAN technologies. Furthermore,certain IoT-enabled objects can communicate using cellularinfrastructure, for instance, using 2G, 3G, 4G (including LTE,LTE-Advanced, and/or LTE-Advanced Pro), and/or 5G technologies.

FIG. 7A is a schematic diagram of one example of an IoT-enabled watch300. The IoT-enabled watch 300 illustrates one example of a smartwearable that can include a front end system implemented in accordancewith one or more features disclosed herein.

FIG. 7B is a schematic diagram of one example of a front end system 301for an IoT-enabled object, such as the IoT-enabled watch 300 of FIG. 7A.The front end system 301 includes a first transceiver-side switch 303, asecond transceiver-side switch 304, a first antenna-side switch 305, asecond antenna-side switch 306, a first power amplifier 307, a secondpower amplifier 308, a duplexer 311, a directional coupler 312, atermination impedance 313, a first band selection filter 315, a secondband selection filter 316, and a third band selection filter 317. Whilenot shown, the front end system 301 can further include any of theoutput matching networks described herein.

In the illustrated embodiment, the first transceiver-side switch 303selects between a Band 26 transmit input pin (B26 TX IN) and a Band 13transmit input pin (B13 TX IN). The second transceiver-side switch 303controls connection of the output of the first power amplifier 307 tothe first band selection filter 315 or the first band selection filter316. Thus, the first power amplifier 307 selectively amplifies Band 26or Band 13, in this example. Additionally, the second power amplifier308 amplifies a Band 12 transmit input pin (B12 TX IN). After suitablefiltering by the band selection filters 315-317, the second antenna-sideswitch 306 selects a desired transmit signal for providing to an antennapin (ANT) via the duplexer 311 and the directional coupler 312. As shownin FIG. 7B, the directional coupler 312 is terminated by the terminationimpedance 313. Additionally, the first antenna-side switch 305 providesa signal received on the antenna pin (ANT) to a desired receive outputpin (four in this example) of the front end system 301. The illustratedfront end system 301 also includes various additional pins to provideadditional functionality, such as enhanced monitoring of transmit power.For instance, front end system 301 includes a directional coupler outputpin (CPL), and feedback pins (B12 RX, B13 RX, and B26 RX) for providingfeedback signals associated with transmit signals (for Band 12, Band 13,and Band 26, respectively) generated by the power amplifiers.

The front end system 301 can incorporate one or more features describedin the sections herein.

FIG. 8A is a schematic diagram of one example of IoT-enabled vehicles321 a-321 d. Each of the IoT-enabled vehicles 321 a-321 d includes afront end system for enabling wireless vehicle-to-vehiclecommunications. The IoT-enabled vehicles 321 a-321 d can include a frontend system implemented in accordance with one or more features disclosedherein.

FIG. 8B is a schematic diagram of another example of a front end system325 for an IoT-enabled object. The front end system 325 includes anantenna-side switch 331, a bypass switch 332, an LNA 333, and a bias andlogic circuit 334.

The front end system 325 includes control pins (C0 and C1) forcontrolling the front end system 325 and a supply voltage pin (VDD) forpowering the front end system 325. The antenna-side switch 331selectively connects an antenna pin (ANT) to a transmit signal pin(TX_IN) or a receive signal pin (RX_OUT). The LNA 333 includes an inputconnected to an LNA input pin (LNA_IN) and an output connected to theLNA output pin (LNA_OUT). The LNA 333 is selectively bypassed by thebypass switch 332. Using external conductors and components, the LNAinput pin (LNA_IN) can be connected to the receive signal pin (RX_OUT)either directly or indirectly (for instance, via a filter or othercomponents). Furthermore, an external power amplifier can provide atransmit signal to the transmit signal pin (TX_IN).

The front end system 325 can incorporate one or more features describedin the sections herein.

FIG. 9A is a schematic diagram of one example of IoT-enabled industrialequipment 340. In the illustrated embodiment, the IoT-enabled industrialequipment 340 includes heliostats 341 for reflecting light to a solarreceiver and turbine 342. The IoT-enabled industrial equipment 340 caninclude one or more front end systems for a variety of purposes, such asproviding angular positional control of the heliostats 341 to controlconcentration of solar energy directed toward the solar receiver andturbine 342. The IoT-enabled industrial equipment 340 can include afront end system implemented in accordance with one or more featuresdisclosed herein.

FIG. 9B is a schematic diagram of another example of a front end system345 for an IoT-enabled object, such as the IoT-enabled industrialequipment 340 of FIG. 9A.

The front end system 345 includes a logic control circuit 350, atransceiver DC blocking capacitor 351, a first antenna DC blockingcapacitor 352, a second antenna DC blocking capacitor 353, an LNA 354, apower amplifier 356, an antenna-side switch 357, a bypass switch 358,and a transceiver-side switch 359. While not shown, the front end system301 can further include any of the output matching networks describedherein.

The front end system 345 includes control pins (CPS, CTX, CSD, ANT_SEL)for controlling the front end system 345. The antenna-side switch 357selectively connects either a first antenna pin (ANT1) or a secondantenna pin (ANT2) to either an output of the power amplifier 356 or thebypass switch 358/input to the LNA 354. Additionally, the bypass switch358 selectively bypasses the LNA 354. Furthermore, the transceiver-sideswitch 359 selectively connected the transceiver pin (TR) to either aninput of the power amplifier 356 or the bypass switch 358/output to theLNA 354. The DC blocking capacitors 351-353 serve to provide DC blockingto provide enhanced flexibility in controlling internal DC biasing ofthe front end system 345.

The front end system 345 can incorporate one or more features describedin the sections herein.

FIG. 10A is a schematic diagram of one example of an IoT-enabled lock360. The IoT-enabled lock 360 illustrates one example of an IoT-enabledobject that can include a front end system implemented in accordancewith one or more features disclosed herein.

FIG. 10B is a schematic diagram of one example of a circuit board 361for the IoT-enabled lock 360 of FIG. 10A. The circuit board 361 includesa front end system 362, which can incorporate one or more featuresdescribed in the sections herein.

FIG. 11A is a schematic diagram of one example of IoT-enabled thermostat370. The IoT-enabled thermostat 370 illustrates another example of anIoT-enabled object that can include a front end system implemented inaccordance with one or more features disclosed herein.

FIG. 11B is a schematic diagram of one example of a circuit board 371for the IoT-enabled thermostat 370 of FIG. 11A. The circuit board 371includes a front end system 372, which can incorporate one or morefeatures described in the sections herein.

FIG. 12A is a schematic diagram of one example of IoT-enabled light 380.The IoT-enabled light 380 illustrates another example of an IoT-enabledobject that can include a front end system implemented in accordancewith one or more features disclosed herein.

FIG. 12B is a schematic diagram of one example of a circuit board 381for the IoT-enabled light 380 of FIG. 12A. FIG. 12B also depicts a baseportion of the IoT-enabled light 380 for housing the circuit board 381.The circuit board 381 includes a front end system 382, which canincorporate one or more features described in the sections herein.

Radio Frequency Systems

FIG. 13A-13F illustrates various schematic block diagrams of examples ofradio frequency systems that include a front end system, such as a frontend module or front end integrated circuit. The radio frequency systemsof FIGS. 13A-13F can incorporate one or more features described in thesections herein. In certain implementations, a radio frequency system,such as any of the radio frequency systems of FIGS. 13A-13F, isimplemented on a circuit board (for instance, a printed circuit board(PCB)) of a wireless communication device, such as a mobile phone, atablet, a base station, a network access point, customer-premisesequipment (CPE), an IoT-enabled object, a laptop, and/or a wearableelectronic device.

FIG. 13A illustrates a schematic block diagram of one example of a radiofrequency system 500. The radio frequency system 500 includes an antenna501, a front end system 10, and a transceiver 505. As was discussedabove, the front end system 10 can incorporate one or more featuresdescribed in the sections herein.

The antenna 501 operates to wirelessly transmit RF signals received viathe antenna-side switch 2. The RF transmit signals can include RFsignals generated by the power amplifier 5 and/or RF signals sent viathe bypass circuit 4. The output matching network 9 receives the signalgenerated by the power amplifier 5. The antenna 501 also operates towirelessly receive RF signals, which can be provided to the LNA 6 and/orthe bypass circuit 4 via the antenna-side switch 2. Although an examplewhere a common antenna is used for transmitting and receiving signals,the teachings herein are also applicable to implementations usingseparate antennas for transmission and reception. Exampleimplementations of the antenna 501 include, but are not limited to, apatch antenna, a dipole antenna, a ceramic resonator, a stamped metalantenna, a laser direct structuring antenna, and/or a multi-layeredantenna.

The transceiver 505 operates to provide RF signals to thetransceiver-side switch 3 for transmission and/or to receive RF signalsfrom the transceiver-side switch 3. The transceiver 505 can communicateusing a wide variety communication technologies, including, but notlimited to, one or more of 2G, 3G, 4G (including LTE, LTE-Advanced,and/or LTE-Advanced Pro), 5G, WLAN (for instance, Wi-Fi), WPAN (forinstance, LTE-M, Bluetooth and/or ZigBee), WMAN (for instance, WiMAX),and/or GPS technologies.

FIG. 13B illustrates a schematic block diagram of another example of aradio frequency system 506. The radio frequency system 506 includes afront end system 20 and a transceiver 505. As was discussed above, thefront end system 20 can incorporate one or more features described inthe sections herein.

FIG. 13C illustrates a schematic block diagram of another example of aradio frequency system 510. The radio frequency system 510 includes anantenna 501, a front end system 511, and a transceiver 505. The frontend system 511 of FIG. 13C is similar to the front end system 10 of FIG.13A, except that the bypass path including the bypass circuit 4 has beenomitted and the antenna-side switch 2′ and the transceiver-side switch3′ include one less throw. Thus, the antenna-side switch 2′ isconfigured to selectively electrically connect the antenna 501 to eitheran input to the LNA 6 or an output of the power amplifier 5.Additionally, the transceiver-side switch 3′ is configured toselectively electrically connect the transceiver 505 to either an outputto the LNA 6 or an input of the power amplifier 5.

FIG. 13D illustrates a schematic block diagram of another example of aradio frequency system 512. The radio frequency system 512 includes afirst antenna 501, a second antenna 502, a front end system 514, and atransceiver 505. The front end system 514 of FIG. 13D is similar to thefront end system 10 of FIG. 13A, except that the antenna-side switch 2″includes an additional throw to provide connectivity to an additionalantenna. Thus, the bypass circuit 4, the power amplifier 5, and/or theLNA 6 can be selectively electrically connected to the first antenna 501and/or the second antenna 502. Although an example of a radio frequencysystem with two antennas is shown, a radio frequency system can includemore or fewer antennas.

The front end systems 10, 20, 511, 514 of FIGS. 13A-13D can incorporateany of the front end systems described herein, such as those describedwith respect to FIGS. 1A-4, or any of the corresponding componentry suchas any of the output matching networks 9 of those front end systems.

Multiple antennas can be included in a radio frequency system for a widevariety of reasons. In one example, the first antenna 501 and the secondantenna 502 correspond to a transmit antenna and a receive antenna,respectively. In a second example, the first antenna 501 and the secondantenna 502 are used for transmitting and/or receiving signalsassociated with different frequency ranges (for instance, differentbands). In a third example, the first antenna 501 and the second antenna502 support diversity communications, such as multiple-inputmultiple-output (MIMO) communications and/or switched diversitycommunications. In a fourth example, the first antenna 501 and thesecond antenna 502 support beamforming of transmit and/or receive signalbeams.

Wireless Communication Devices

FIG. 14A is a schematic diagram of one example of a wirelesscommunication device 650. The wireless communication device 650 includesa first antenna 641, a wireless personal area network (WPAN) system 651,a transceiver 652, a processor 653, a memory 654, a power managementblock 655, a second antenna 656, and a front end system 657.

Any of the suitable combination of features disclosed herein can beimplemented in the wireless communication device 650. For example, theWPAN system 651 and/or the front end system 657 can be implemented usingany of the features described above and/or in the sections below.

The WPAN system 651 is a front end system configured for processingradio frequency signals associated with personal area networks (PANs).The WPAN system 651 can be configured to transmit and receive signalsassociated with one or more WPAN communication standards, such assignals associated with one or more of LTE-M (LTE Machine TypeCommunication), Bluetooth, ZigBee, Z-Wave, Wireless USB, INSTEON, IrDA,or Body Area Network. In another embodiment, a wireless communicationdevice can include a wireless local area network (WLAN) system in placeof the illustrated WPAN system, and the WLAN system can process Wi-Fisignals.

FIG. 14B is a schematic diagram of another example of a wirelesscommunication device 660. The illustrated wireless communication device660 of FIG. 14B is a device configured to communicate over a PAN. Thiswireless communication device 660 can be relatively less complex thanthe wireless communication device 650 of FIG. 8A. As illustrated, thewireless communication device 660 includes an antenna 641, a WPAN system651, a transceiver 662, a processor 653, and a memory 654. The WPANsystem 660 can include any suitable combination of features disclosedherein. For example, the WPAN system 651 can be implemented using any ofthe features described above and/or in the sections below.

FIG. 14C is a schematic diagram of another example of a wirelesscommunication device 800. The wireless communication device 800 includesa baseband system 801, a transceiver 802, a front-end system 803, one ormore antennas 804, a power management system 805, a memory 806, a userinterface 807, and a battery 808.

The wireless communication device 800 can be used communicate using awide variety of communications technologies, including, but not limitedto, 2G, 3G, 4G (including LTE, LTE-Advanced, and LTE-Advanced Pro), 5G,WLAN (for instance, Wi-Fi), WPAN (for instance, LTE-M, Bluetooth andZigBee), WMAN (for instance, WiMAX), and/or GPS technologies.

The transceiver 802 generates RF signals for transmission and processesincoming RF signals received from the antennas 804. It will beunderstood that various functionalities associated with the transmissionand receiving of RF signals can be achieved by one or more componentsthat are collectively represented in FIG. 14C as the transceiver 802. Inone example, separate components (for instance, separate circuits ordies) can be provided for handling certain types of RF signals.

The front-end system 803 aids in conditioning signals transmitted toand/or received from the antennas 804. In the illustrated embodiment,the front-end system 803 includes one or more power amplifiers (PAs)811, one or more low noise amplifiers (LNAs) 812, one or more filters813, one or more switches 814, and one or more duplexers 815, and one ormore output matching networks 816. However, other implementations arepossible.

For example, the front-end system 803 can provide a number offunctionalities, including, but not limited to, amplifying signals fortransmission, amplifying received signals, filtering signals, switchingbetween different bands, switching between different power modes,switching between transmission and receiving modes, duplexing ofsignals, multiplexing of signals (for instance, diplexing ortriplexing), or some combination thereof.

Any of the suitable combination of features disclosed herein can beimplemented in the wireless communication device 800. For example, thefront end system 803 can be implemented using any of the featuresdescribed above and/or in the sections below.

In certain implementations, the wireless communication device 800supports carrier aggregation, thereby providing flexibility to increasepeak data rates. Carrier aggregation can be used for both FrequencyDivision Duplexing (FDD) and Time Division Duplexing (TDD), and may beused to aggregate a plurality of carriers or channels. Carrieraggregation includes contiguous aggregation, in which contiguouscarriers within the same operating frequency band are aggregated.Carrier aggregation can also be non-contiguous, and can include carriersseparated in frequency within a common band or in different bands.

The antennas 804 can include antennas used for a wide variety of typesof communications. For example, the antennas 804 can include antennasfor transmitting and/or receiving signals associated with a wide varietyof frequencies and communications standards.

In certain implementations, the antennas 804 support MIMO communicationsand/or switched diversity communications. For example, MIMOcommunications use multiple antennas for communicating multiple datastreams over a single radio frequency channel. MIMO communicationsbenefit from higher signal to noise ratio, improved coding, and/orreduced signal interference due to spatial multiplexing differences ofthe radio environment. Switched diversity refers to communications inwhich a particular antenna is selected for operation at a particulartime. For example, a switch can be used to select a particular antennafrom a group of antennas based on a variety of factors, such as anobserved bit error rate and/or a signal strength indicator.

The wireless communication device 800 can operate with beamforming incertain implementations. For example, the front-end system 803 caninclude phase shifters having variable phase controlled by thetransceiver 802. Additionally, the phase shifters are controlled toprovide beam formation and directivity for transmission and/or receptionof signals using the antennas 804. For example, in the context of signaltransmission, the phases of the transmit signals provided to theantennas 804 are controlled such that radiated signals from the antennas804 combine using constructive and destructive interference to generatean aggregate transmit signal exhibiting beam-like qualities with moresignal strength propagating in a given direction. In the context ofsignal reception, the phases are controlled such that more signal energyis received when the signal is arriving to the antennas 804 from aparticular direction. In certain implementations, the antennas 804include one or more arrays of antenna elements to enhance beamforming.

The baseband system 801 is coupled to the user interface 807 tofacilitate processing of various user input and output (I/O), such asvoice and data. The baseband system 801 provides the transceiver 802with digital representations of transmit signals, which the transceiver802 processes to generate RF signals for transmission. The basebandsystem 801 also processes digital representations of received signalsprovided by the transceiver 802. As shown in FIG. 14C, the basebandsystem 801 is coupled to the memory 806 of facilitate operation of thewireless communication device 800.

The memory 806 can be used for a wide variety of purposes, such asstoring data and/or instructions to facilitate the operation of thewireless communication device 800 and/or to provide storage of userinformation.

The power management system 805 provides a number of power managementfunctions of the wireless communication device 800. In certainimplementations, the power management system 805 includes a PA supplycontrol circuit that controls the supply voltages of the poweramplifiers 811. For example, the power management system 805 can beconfigured to change the supply voltage(s) provided to one or more ofthe power amplifiers 811 to improve efficiency, such as power addedefficiency (PAE).

As shown in FIG. 14C, the power management system 805 receives a batteryvoltage from the battery 808. The battery 808 can be any suitablebattery for use in the wireless communication device 800, including, forexample, a lithium-ion battery.

Some or all of the front end systems 656, 803 or WPAN systems 651 ofFIGS. 14A-14C can incorporate any of the front end systems describedherein, such as those described with respect to FIGS. 1A-4, or any ofthe corresponding componentry such as any of the output matchingnetworks 9 of those front end systems.

FIG. 15 is a schematic diagram of an example RF module 2010A thatincludes a system-on-chip 2012A, an RF front end IC 2012B, a crystal2012C, and an integrated antenna 2014 according to an embodiment. Thesystem-on-chip 2012A can include one or more of a transceiver, processor(e.g., a baseband processor), and memory. The RF front end IC 2012B caninclude any of the front end components described herein, such as any ofthe front end systems of FIGS. 1A-4. For example, the RF front end IC2012B can include for example any of the power amplifiers, switches, lownoise amplifiers, and output matching networks described herein. In someembodiments, the RF front end IC 2012B is a semiconductor-on-insulator(e.g., silicon-on-insulator) die implementing FET-based power amplifiersuch as the cascade power amplifier of FIG. 3. The RF module 2010A canbe a system in a package.

FIG. 15 shows the RF module 2010 a in plan view without a top shieldinglayer, which can also be included. As illustrated, the RF module 2010Aincludes the component 2012A-2012C on a package substrate 2016, theantenna 2014 on the package substrate 2016, and wire bonds 2018 attachedto the package substrate 2016 and surrounding the components2012A-2012C. The antenna 2014 of the RF module 2010A is outside of an RFshielding structure around the components 2012A-2012C. Accordingly, theantenna 2014 can wirelessly receive and/or transmit RF signals withoutbeing shielded by the shielding structure around the components2012A-2012C. At the same time, the shielding structure can provide RFisolation between the components 2012A-2012C and the antenna 2014 and/orother electronic components.

The components 2012A-2012C can include any suitable circuitry configuredto receive, process, and/or provide an RF signal. In certainimplementations, the RF front end IC 2012B can include a poweramplifier, a low-noise amplifier, an RF switch, a filter, a matchingnetwork, or any combination thereof, and can be clocked by a signalderived from the crystal 2012C. An RF signal can have a frequency in therange from about 30 kHz to 300 GHz. In accordance with certaincommunications standards, an RF signal can be in a range from about 450MHz to about 6 GHz, in a range from about 700 MHz to about 2.5 GHz, orin a range from about 2.4 GHz to about 2.5 GHz. In certainimplementations, the RF component 2012 can receive and/or providesignals in accordance with a wireless personal area network (WPAN)standard, such as LTE-M, Bluetooth, ZigBee, Z-Wave, Wireless USB,INSTEON, IrDA, or Body Area Network. In some other implementations, theRF component and receive and/or provide signals in accordance with awireless local area network (WLAN) standard, such as Wi-Fi.

The antenna 2014 can be any suitable antenna configured to receiveand/or transmit RF signals. The antenna 2014 can be a folded monopoleantenna in certain applications. The antenna 2014 can be any suitableshape. For instance, the antenna 2014 can have a meandering shape asshown in FIG. 15. In other embodiments, the antenna can be U-shaped,coil shaped, or any other suitable shape for a particular application.The antenna 2014 can transmit and/or receive RF signals associated withthe RF front end IC 2012B. The antenna 2014 can occupy any suitableamount of area of the packaging substrate 2016. For instance, theantenna 2014 can occupy from about 10% to 75% of the area of the packagesubstrate 2016 in certain implementations.

The antenna 2014 can be printed on the packaging substrate 2016. Aprinted antenna can be formed from one or more conductive traces on thepackaging substrate 2016. The one or more conductive traces can beformed by etching a metal pattern on the packaging substrate 2016. Aprinted antenna can be a microstrip antenna. Printed antennas can bemanufactured relatively inexpensively and compactly due to, for example,their 2-dimensional physical geometries. Printed antennas can have arelatively high mechanical durability.

The package substrate 2016 can be a laminate substrate. The packagesubstrate 2016 can include one or more routing layers, one or moreinsulating layers, a ground plane, or any combination thereof. Incertain applications, the package substrate can include four layers. TheRF front end IC 2012B can be electrically connected to the antenna 2014by way of metal routing in a routing layer of the packaging substrate2016 in certain applications.

The wire bonds 2018 are part of an RF shielding structure around the RFcomponent 2012. An RF shielding structure can be any shielding structureconfigured to provide suitable shielding associated with RF signals. Thewire bonds 2018 can provide RF isolation between the antenna 2014 andsome or all of the components 2012A-2012C so as to preventelectromagnetic interference between these components from significantlyimpacting performance of the antenna 2014 and/or some or all of thecomponents 2012A-2012C. The wire bonds 2018 can surround the RFcomponent 2012 as illustrated. The wire bonds 2018 can be arrangedaround the components 2012A-2012C in any suitable arrangement, which canbe rectangular as illustrated or non-rectangular in some otherimplementations. In the RF module 2010A illustrated in FIG. 15, the wirebonds 2018 form four walls around the components 2012A-2012C. The wirebonds 2018 can be arranged such that adjacent wire bonds are spacedapart from each other by a distance to provide sufficient RF isolationbetween the components 2012A-2012C and other electronic components.

FIG. 15 illustrates an RF module in accordance with the principles andadvantages discussed herein. The RF module can be selectively shielded,where various RF components can be implemented within a shieldingstructure. For instance, FIG. 15 shows an example of an RF componentthat includes three different elements. Other RF components canalternatively or additionally be implemented. A conformal layer can bedisposed along at least one side the RF component of the RF module inembodiments in which a shielding layer is formed after singulation ofthe RF modules. The conformal structure can include any suitableconductive material. For example, the conductive conformal structure caninclude the same conductive material as the shielding layer in certainapplications

Any of the embodiments described above can be implemented in associationwith mobile devices such as cellular handsets. The principles andadvantages of the embodiments can be used for any systems or apparatus,such as any uplink wireless communication device, that could benefitfrom any of the embodiments described herein. The teachings herein areapplicable to a variety of systems. Although this disclosure includesexample embodiments, the teachings described herein can be applied to avariety of structures. Any of the principles and advantages discussedherein can be implemented in association with RF circuits configured toprocess signals having a frequency in a range from about 30 kHz to 300GHz, such as in a frequency range from about 400 MHz to 25 GHz.

Aspects of this disclosure can be implemented in various electronicdevices. Examples of the electronic devices can include, but are notlimited to, consumer electronic products, parts of the consumerelectronic products such as packaged radio frequency modules, radiofrequency filter die, uplink wireless communication devices, wirelesscommunication infrastructure, electronic test equipment, etc. Examplesof the electronic devices can include, but are not limited to, a mobilephone such as a smart phone, a wearable computing device such as a smartwatch or an ear piece, a telephone, a television, a computer monitor, acomputer, a modem, a hand-held computer, a laptop computer, a tabletcomputer, a microwave, a refrigerator, a vehicular electronics systemsuch as an automotive electronics system, a robot such as an industrialrobot, an Internet of things device, a stereo system, a digital musicplayer, a radio, a camera such as a digital camera, a portable memorychip, a home appliance such as a washer or a dryer, a peripheral device,a wrist watch, a clock, etc. Further, the electronic devices can includeunfinished products.

Unless the context indicates otherwise, throughout the description andthe claims, the words “comprise,” “comprising,” “include,” “including”and the like are to generally be construed in an inclusive sense, asopposed to an exclusive or exhaustive sense; that is to say, in thesense of “including, but not limited to.” Conditional language usedherein, such as, among others, “can,” “could,” “might,” “may,” “e.g.,”“for example,” “such as” and the like, unless specifically statedotherwise, or otherwise understood within the context as used, isgenerally intended to convey that certain embodiments include, whileother embodiments do not include, certain features, elements and/orstates. The word “coupled”, as generally used herein, refers to two ormore elements that may be either directly coupled, or coupled by way ofone or more intermediate elements. Likewise, the word “connected”, asgenerally used herein, refers to two or more elements that may be eitherdirectly connected, or connected by way of one or more intermediateelements. Additionally, the words “herein,” “above,” “below,” and wordsof similar import, when used in this application, shall refer to thisapplication as a whole and not to any particular portions of thisapplication. Where the context permits, words in the above DetailedDescription using the singular or plural number may also include theplural or singular number respectively.

While certain embodiments have been described, these embodiments havebeen presented by way of example only, and are not intended to limit thescope of the disclosure. Indeed, the novel filters, multiplexer,devices, modules, wireless communication devices, apparatus, methods,and systems described herein may be embodied in a variety of otherforms. Furthermore, various omissions, substitutions and changes in theform of the filters, multiplexer, devices, modules, wirelesscommunication devices, apparatus, methods, and systems described hereinmay be made without departing from the spirit of the disclosure. Forexample, while blocks are presented in a given arrangement, alternativeembodiments may perform similar functionalities with differentcomponents and/or circuit topologies, and some blocks may be deleted,moved, added, subdivided, combined, and/or modified. Each of theseblocks may be implemented in a variety of different ways. Any suitablecombination of the elements and/or acts of the various embodimentsdescribed above can be combined to provide further embodiments. Theaccompanying claims and their equivalents are intended to cover suchforms or modifications as would fall within the scope and spirit of thedisclosure.

What is claimed is:
 1. A power amplifier system comprising: asemiconductor-on-insulator die; a power amplifier implemented on thesemiconductor-on-insulator die and configured to amplify a radiofrequency input signal having a fundamental frequency, the poweramplifier including an input configured to receive the radio frequencyinput signal and an output configured to provide an amplified radiofrequency signal; and an output matching circuit implemented on thesemiconductor-on-insulator die and including first and secondsecond-order harmonic rejection circuits configured to resonate at abouttwo times the fundamental frequency and a third order harmonic rejectioncircuit configured to resonate at about three times the fundamentalfrequency.
 2. The power amplifier system of claim 1 further comprising athird second-order harmonic rejection circuit.
 3. The power amplifiersystem of claim 2 wherein the first and second second-order harmonicrejection circuits are harmonic short circuits and the thirdsecond-order harmonic rejection circuit is a harmonic open circuit. 4.The power amplifier system of claim 3 wherein the third-order harmonicrejection circuit is a harmonic open circuit.
 5. The power amplifiersystem of claim 4 wherein the first second-order harmonic rejectioncircuit is positioned between the output of the power amplifier and apower low supply voltage, the third-order harmonic rejection circuit ispositioned between the output of the power amplifier and a first node,the third second-order harmonic circuit is positioned between the firstnode and a second node, and the second second-order harmonic circuit ispositioned between the second node and the power low supply voltage. 6.The power amplifier system of claim 1 further comprising biasingcircuitry implemented on the die and configured to bias the poweramplifier, and a switch implemented on the die and configured to controlconnection of signal paths to an antenna.
 7. The power amplifier systemof claim 1 wherein the power amplifier includes two field effecttransistors arranged in a cascode configuration.
 8. The power amplifiersystem of claim 1 wherein the third-order harmonic rejection circuitincludes a capacitor and an inductor, and the inductor is implemented asa surface mount device on a module supporting thesemiconductor-on-insulator die.
 9. The power amplifier system of claim 8wherein the first second-order harmonic rejection circuit includes atunable bank of at least two capacitors.
 10. The power amplifier systemof claim 6 further comprising a biasing circuit wherein the biasingcircuit including a decoupling capacitor and a choke inductor, the chokeinductor embedded in a substrate of a module supporting thesemiconductor-on-insulator die.
 11. A semiconductor-on-insulator diecomprising: a power amplifier configured to amplify a radio frequencyinput signal having a fundamental frequency, the power amplifierincluding an input configured to receive the radio frequency inputsignal and an output configured to provide an amplified radio frequencysignal; and an output matching circuit including first and secondsecond-order harmonic rejection circuits configured to resonate at abouttwo times the fundamental frequency and a third order harmonic rejectioncircuit configured to resonate at about three times the fundamentalfrequency.
 12. The die of claim 11 further comprising a thirdsecond-order harmonic rejection circuit.
 13. The die of claim 12 whereinthe first and second second-order harmonic rejection circuits areharmonic short circuits and the third second-order harmonic rejectioncircuit is a harmonic open circuit.
 14. The die of claim 13 wherein thethird-order harmonic rejection circuit is a harmonic open circuit. 15.The die of claim 11 wherein the power amplifier includes two fieldeffect transistors arranged in a cascode configuration.
 16. The die ofclaim 11 wherein the die further includes biasing circuitry configuredto bias the power amplifier, a switch configured to control connectionof signal paths to an antenna, and a controller configured to controlthe power amplifier and the switch.
 17. A mobile device comprising: amodule including a semiconductor-on-insulator die mounted thereon, thedie including a power amplifier configured to amplify a radio frequencyinput signal having a fundamental frequency, the power amplifierincluding an input configured to receive the radio frequency inputsignal and an output configured to provide an amplified radio frequencysignal, the die further including an output matching circuit includingfirst and second second-order harmonic rejection circuits configured toresonate at about two times the fundamental frequency and a third orderharmonic rejection circuit configured to resonate at about three timesthe fundamental frequency; and a radio frequency antenna.
 18. The mobiledevice of claim 17 wherein the antenna is included on the module. 19.The mobile device of claim 17 further comprising a biasing circuitincluding a decoupling capacitor and a choke inductor, the decouplingcapacitor implemented on the die and the choke inductor embedded in asubstrate of the module.
 20. The mobile device of claim 17 furtherwherein the third order harmonic rejection circuit includes a capacitorimplemented on the die and a surface mounted inductor mounted on themodule.